There were harrowing near misses but Christchurch has emerged from a magnitude 5.7 quake with no deaths and little damage and must wait to see what happens next.
Two kids from Taylors Mistake, on the city's southeastern extremity, were clipped by rocks that fell on a cliff face.
Three people were also in a cave at the sight and a couple enjoying a Valentine's Day picnic ran for their lives, media reported.
The quake struck shortly after 1pm on Sunday just a day after Prime Minister John Key visited the city he grew up in to highlight its rejuvenation and eight days before the fifth anniversary of a devastating 6.3 quake that killed 185 people.
No serious injuries have been reported and the city's infrastructure has mostly held up.
"What we have to take from this is our city is stronger than it was five years ago and it's better able to respond," Mayor Lianne Dalziel said.
Emma Russell and her boyfriend were about 50m from a rockfall and say they are glad they decided against sitting closer to the edge.
"You just heard all the cliffs give way around us," they told The Press.
A magnitude 4.0 aftershock was recorded after 6pm and scientists say there is a 50 per cent chance of another quake above 5.
"It does jolt you a bit but you just have to carry on," Ocean Cafe & Bar co-owner Julie-Anne Pritchard told NZ Newswire after diners at her cafe watched a cliff fall into the sea.
"We thought this will be a wee short one but it wasn't," Ms Pritchard said.
Diners were in tears but some stayed and ate their meals.
She checked her home on Scarborough Hill and found possessions fallen from shelves.
"All the houses up there are just covered in dust," she said.
Emergency services geared up but have been scaled back.
Ms Dalziel says people will feel vulnerable.
"It really is a real set-back psychologically for the city," she said.
Cliffs collapsed at Whitewash Heads near Taylors Mistake and at Godley Head, Christchurch City Council says.
Material also came off the cliffs behind Wakefield Avenue at the back of a bowling club, but nothing reached the road and considerable material has also come off Peacocks' Gallop.
There was traffic chaos as people rushed home to check on loved ones - water mains are burst and damaged mobile phone towers are being repaired.
A magnitude 5.7 quake has been recorded near Christchurch, with the city experiencing aftershocks. (AAP) Source: AAP
Christchurch Hospital reports no increase above normal in patients and it's checking minor damage to its buildings.
It's moving mothers and babies from Burwood Hospital in the eastern suburbs as a precaution. Shopping malls were also cleared.
Mr Key said it was good news there was no loss of life or injuries.
He said the new buildings in Christchurch are stronger and people should not be concerned the quake was a whole new thing in its own right. It was connected to the previous quakes.
There should be a very high confidence for Cantabrians but it's a very sharp reminder for them, he told Newstalk ZB.
The quake was centred 15km east of Christchurch and was 31km deep - with people as far north as Palmerston North and as far south as Dunedin reporting they felt it.
